The present invention relates generally to sorters. More specifically, it relates to a sorter incorporating a stapler for stapling stacks of sheets.
A conventional copying machine may be provided with a sorter for sorting and storing image-formed sheets, and a type of sorter includes a stapler for stapling stacks of sheets.
Japanese Patent Laying-Open No. 231757/1989 discloses one of the conventional sorters which incorporates a stapler. This sorter is provided with a plurality of receiving bins into which sheets are sorted in order. The bins are vertically disposed and vertically movable. A sheet supplier provided near the lower end of the bins supplies sheets discharged from a copying machine into the bins. A stapler for stapling the stacks of sheets stored in the bins is provided in the sheet supplier.
In this conventional sorter, a predetermined gap is provided between adjacent bins through which sheets are transported from the sheet supplier into the bins. The stack of sheets stored in each bin is stapled by the stapler. The stapler is rotatable through a predetermined angle between a drawn position, to clear the movement of the bins, and a stapling position at which the stapling operation is executed.
Japanese Patent Laying-Open No. 23154/1990 discloses another sorter having a plurality of bins each of which is immobile. Sheets from a copying machine are transported into the bins by corresponding claws provided in a transporting mechanism. In the sorter is a vertically movable stapler.
The stapling operation of the sorter is performed as follows: the stapler is moved vertically; a nipper draws a stack of sheets from a bin into a stapling position; the stapler staples the stack of sheets; and the nipper moves the stack of sheets back into the bin.
In the sorter disclosed in Japanese Patent Laying-Open No. 231757/1989, the stapler is provided in the sheet supplier, wherein the stapler is potentially an obstruction to the vertical movement of the bins. Consequently, it is necessary to provide a mechanism for rotating the stapler between the stapling position and the drawn position, which thus complicates the structure. In the sorter disclosed in Japanese Patent Laying-Open No. 23154/1990, it is necessary to provide, in addition to the stapler, a device which draws each stack of sheets from, and returns each stack into the bins, therein complicating the structure as well.
These two conventional sorters, however, cannot accommodate any number of stacks of sheets greater than the number of bins. Therefore, when a larger number of copy bundles are to be produced, an operator must empty stapled stacks of sheets from the bins in order to allow the succeeding stacks of sheets to be formed in the bins. A plurality of sorters could be provided in order to process a larger number of copies but they would occupy a greater amount of space.
Japanese Patent Laying-Open No. 165270/1988 discloses a sorter having a sorting portion and a stacking portion. In this sorter, stacks of sheets temporarily stored in the sorting portion are transported to the stacking portion, where they are stapled by a stapler provided therein. Accordingly, the sorter can handle a larger number of stacks of sheets than the number of bins provided in the sorting portion.
In the sorter disclosed in Japanese Patent Laying-Open No. 165270/1988, however, the stacks of sheets temporarily stored in the sorting portion tend to become disarranged while they are transported toward the stacking portion, making it less manageable to achieve properly arranged and stapled stacks within the stacking portion.